A hard disc drive (i.e., a HDD) is a block-based data storage device that stores and retrieves digital information using non-volatile memory within one or more rotating platters of the HDD. The typical HDD includes one or more writer assemblies that fly above a corresponding platter surface and transform electrical currents into a magnetic fields to write data to the platters of the HDD.
A preamplifier applies the desired electrical current through one or more write coils connected in series within each writer assembly. The write coils within each writer assembly function to transform the electrical current into a magnetic field and direct the resulting magnetic flux density through a write pole to write data to the platters of the HDD. Since each of the one or more write coils are wound in series within each writer assembly, there is no capability to tune the write current individually to each of the write coils within each writer assembly of the HDD.